1. Technical Field
The present disclosure relates to a communication method and a communication device and specifically relates to a communication method and a communication device for suppressing interference in a WLAN (wireless local area network).
2. Description of the Related Art
A 60-GHz millimeter-wave network that requires no license is receiving increasing attention. The wireless HD technology is the first industry standard for the 60-GHz millimeter wave and enables multi-gigabit wireless streaming of high-definition sounds, videos, and data between home electrical appliances, personal computers, and portable devices.
As another multi-gigabit wireless communication technology operating on the 60-GHz millimeter frequency band, the WiGig (Wireless Gigabit) technology is available. The WiGig technology is standardized by IEEE (Institute of Electrical and Electronics Engineers) as the IEEE 802.11ad standard (see IEEE 802.11ad-2012). The WiGig technology uses a wide channel bandwidth of 2.16 GHz to provide PHY (physical layer) data rates of up to 6.7 Gbps.
The MAC (Medium Access Control) layer of WiGig supports a centralized network architecture, such as an infrastructure BSS (basic service set) or a PBSS (personal BSS). In this architecture, a central coordinator (for example, an AP (access point) or a PCP (personal BSS control point), hereinafter referred to as a PCP/AP) transmits DMG (directional multi-gigabit) beacons to synchronize all STAs (stations) on the network.
On the MAC layer of WiGig, a mechanism called PCP/AP clustering is introduced in order to enable spatial sharing and interference mitigation with other BSSs using the same channel. In the PCP/AP clustering, transmission is scheduled so that a clustering-capable PCP/AP that is a member of a cluster performs transmission in a period that does not overlap those of other members in the same cluster.
In the PCP/AP clustering, scheduling information regarding channel time allocation is included in an ESE (extended schedule element). A PCP/AP transmits a SMG beacon including one or more ESEs in accordance with a time-division system.
As a technology for achieving a data rate higher than that of existing WiGig (hereinafter referred to as legacy WiGig) devices, a technology called NG60 (next-generation 60 GHz) WiGig (hereinafter referred to as NG60_WiGig) is being developed. In order for NG60_WiGig to achieve PHY data rates of up to several tens of Gbps, a technology for supporting MIMO (multiple input, multiple output) transmission and a variable channel bandwidth while maintaining downward compatibility with legacy WiGig devices is desirable.
In an NG60_WiGig network, a PCP/AP based on NG60_WiGig that is a coordinator communication device (hereinafter referred to as an NG60_PCP/AP) can coexist with a neighboring PCP/AP based on legacy WiGig (hereinafter referred to as a legacy PCP/AP) in the same PCP/AP cluster or in a different PCP/AP cluster due to downward compatibility.
Meanwhile, an ESE based on NG60_WiGig (hereinafter referred to as an NG60_ESE) has a format different from that of an ESE based on legacy WiGig (hereinafter referred to as a legacy ESE), and therefore, a legacy PCP/AP has difficulty in decoding an NG60_ESE transmitted by an NG60_PCP/AP. Because of the difficulty in decoding an NG60_ESE, a legacy PCP/AP has difficulty in obtaining scheduling information included in the NG60_ESE. Accordingly, the legacy PCP/AP has difficulty in rescheduling channel time allocation thereof or performing any other appropriate operations.